Emmett O'Byrne (born 30 November 1973) is an Irish historian whose primary research interests are the history of Medieval Ireland and Early Modern Ireland, focusing in particular on Gaelic Ireland. Further research interests include the development of the common law in Ireland from 1169, competing laws among the marches of medieval Ireland and the peoples and frontiers of medieval Europe.

O'Byrne was educated at De La Salle College, Wicklow and at St Peter's College, Wexford. From 1992 to 19955 he studied history and classics in University College Dublin, receiving his BA in 1995. He attended Trinity College Dublin to study for an MPhil in medieval history, completing his masters in 1996. He spent much of 1997 working in northern Israel on Kibbutz Ga'aton, travelling widely through the Middle East. In late 1997, he returned to Ireland to begin his doctoral thesis on the Irish of Leinster 1156–1606 for which he was awarded his doctorate in July 2001.[1]

During the years 1999–2003, OByrne worked as a contributor to the Royal Irish Academy's forthcoming Dictionary of Irish Biography, completing some two hundred and twenty eight biographical articles on Irish historical figures. Further publications have appeared in various collections of essays on Irish history and contributions to the Medieval Encyclopaedia of Ireland. His book War, politics and the Irish of Leinster, 1156–1606 was published by Four Courts Press in 2003, receiving critical acclaim in a number of international journals such as Speculum (2005),[2]The English Historical Review (2005)[3] and Celtica (2007).[4]

In September 2003 he was awarded a post doctoral fellowship at the Mícheál Ó Cléirigh Institute for the Study of Irish History and Civilisation at University College Dublin, holding that position until its expiration in late 2006. In the interim years, O'Byrne with Dr. Edel Breathnach organised a major[citation needed] international conference in 2005 at University College Dublin entitled "The March in Medieval West, 1000–1500", attracting several internationally renowned historians.[citation needed] With Dr. Jenifer Ní Ghrádaigh of University College Cork, he has edited the proceedings of this conference for publication either in late 2009 or early 2010.[citation needed]

In 2006 O'Byrne was appointed historical advisor to the Wicklow 400 Commemoration Celebrations, writing a number of articles in the Wicklow Times and the Wicklow People newspapers.

Since 2007 he has been employed by Carlow Institute of Technology as a lecturer in law, having received his BA in Legal Studies from the Dublin Institutes of Technology in November 2005. In March 2009 he was elected to serve a three-year term on the Academic Council of Carlow Institute of Technology.

O'Byrne is currently completing the biography of Feagh McHugh O'Byrne (d.1597) and another major work on Irish medieval history for publication.